Key-operated lock



25, 1956 w. H. MANTHORNE 3,230,749

KEY-OPERATED LOCK Filed Dec. 5, 1963 \NVENTOR W.H.M GENE TT NEY United States Patent 3,230,749 KEY-OPERATED LDCK William H. Manthorne, Indianapolis, Ind., assignor to Western Electric Company, Incorporated, New York, N.Y., a corporation of New York I Filed Dec. 3, 1963, Ser. No. 327,745

3 Claims. (Cl. 70421) This invention relates to a key-operated lock of the type in which key actuation moves a plurality of tumblers into such positions that they permit retraction of a bolt. It is an object of the invention to provide an improved key-operated lock of this type which is diflicult to pick.

Picking of a lock of the above-indicated type necessitates the simultaneous holding of the various tumblers in their proper positions. Generally this is accomplished with two separate lock-picking instruments, one for urging the bolt against the tumblers and one for setting successive tumblers to their proper positions.

A lock constructed in accordance with the present invention is provided with a special master tumbler which is of such dimensions that the bolt may be made to bear against only the master tumbler, and not against the other tumblers, until such time as the master tumbler is so posiioned as to permit bolt retraction. Accordingly, the master tumbler must beset first, in a lock-picking operation, since only then can the bolt be made to bear against the other tumblers. The master tumbler is associated with each of the conventional tumblers in such a way "that movement of the master tumbler from its normal position to' the bolt retracting position drives the conventional tumblers in the same direcion. Accordingly, the lock-picking instrument which is used to move the master "tumbler into unlocked or bolt retracting position must be of sufficient strength to move all of the tumblers against,

the combined force of all of their biasing springs. A Accordingly, a further object of the invention is to provide-an improved key-operated lock in which picking er the lock necessitates that the instrument for setting the The tumblers are pivotable through different predeter- "mined angles from their normal positions by an operat- {ing key to align a notch in the edge of each tumbler with the bolt edge to permit bolt retraction. In accordance with the preferred embodiment of the invention, the master tumbler is mounted for pivotal movement about the same axis and has a radius sufficient-ly greater than the radius of the other tumblers that the bolt edge can engage only the master tumbler until the latter has been pivoted such that the bolt edge may enter the notch in the master tumbler. Accordingly, picking of the lock requires that the master tumbler be properly positioned before bolt pressure can be brought against the other tumblers. A pin is connected to the master tumbler and extends past each of the other tumblers such that pivotal movement of the master tumbler in the lock opening direction is necessarily accompanied by movement of the other tumblers away from their normal position. Accordingly, the instrument used to position the master tumbler in a lock-picking operation must be of sufficient strength to move all of the tumblers simultaneously against the combined strength of their springs. The various tumblers may be selectively positioned by the proper key since lock opening movement of the other tumblers may be independent of movement of the master tumbler.

This invention, together with further objects and ad- Patented Jan. 25, 1966 "ice vantages thereof, will best be understood by reference to the following description taken in connection with the accompanying drawings, in which:

FIG. 1 is a front view of a key-operated lock incorporating .an embodiment of the present invention; and

FIG. 2 is an exploded perspective view of the same lock.

In the drawing the invention is shown applied to a keyoperated lock of otherwise conventional design. More particularly, the lock may be of the type shown in Patent No. 1,957,586 issued May 8, 1934, to Gutman.

The lock includes a bolt 11 which is slidably mounted within a housing 12. A plurality of tumblers 13 are pivotally mounted on a pin 14 and biased in the counterclockwise direction by individual springs 15.

Arcuate edges 16 of the tumblers 13 normally lie in the path of an edge 17 of the bolt assembly such that bolt retraction is prevented. When the proper key 23 is inserted in a barrel 21 and is rotated in a clockwise direction, the various tumblers 13 are pivoted through different predetermined angles by pressure of corresponding portions of the key against the left-hand edges thereof. This brings a notch 22 in each of the tumblers 13 into alignment with the edge 17 of the bolt 11 such that the bolt may be retracted.

As will be appreciated by those skilled in the art, the portion of the bolt assembly which engages and is restrained by the tumblers may be the bolt itself, an integral or rigidly associated member, or it may be a nonintegral but drivingly associated member. The latter is the case in a cylinder-type lock, wherein the cylinder is drivingly associated with the bolt and is the member which is directly restrained by the pin-type tumblers. Where it is specified herein that the bolt engages and is restrained by tumblers, it is intended that such statement be interpreted broadly, to include either direct or indirect engagement of bolt and tumblers.

In accordance with the illustrated embodiment of the invention, a master tumbler 23 is provided which is pivotable about the pin 14 and is biased in a counterclockwise direction by a spring 25, in the manner of the other tumblers 13. The arcuate edge 26 of the master tumbler 23 has a slightly greater radius, about the pin 14, than the arcuate edges 16 of the other tumblers.

Accordingly, the edge 17 of the bolt cannot normally be made to bear against the arcuate edges 16 of the tumblers .13. If an attempt is made to pick the lock, it is necessary that the master tumbler 23 first be positioned to bring its slot 32 opposite the edge 17 of the bolt, in order that the bolt edge 17 may be made to bear against the other tumblers.

The left-hand edge of the master tumbler 23 is provided with an ear 34 which extends in a counterclockwise direction beyond the left-hand edges of the conventional tumblers 13 when all tumblers are in their normal positions. A pin 35 is rigidly secured to the ear 34 of the master tubler and extends alongside and immediately adjacent to the left-hand edges of the conventional tumblers 13. The pin 35 serves as a one-way connection between the master tumbler and the conventional tumblers such that lock-opening movement of the master tumbler is necessarily accompanied by movement of the other tumblers away from their normal positions, while lock-opening movement of the other tumblers may be independent of movement of the master tumbler,

With the lock constructed in this manner, further difficulty is placed in the path of a person seeking to pick the lock. Because of the greater radius of the arcuate edge of the master tumbler it is necessary that the lock picker first properly position the master tumbler such that the bolt edge 17 may enter the slot 32 and thus be brought to bear against the arcuate edges of the conventional tumblers 13. Because of the one-way connection between the master tumbler 23 and the conventional tumblers 13, embodied in the pin 35 such initial movement of themaster tumbler 23 is necessarily accompanied by movement of the conventional tumblers 13 in the same direction. This is turn requires that the instrument employed to pivot the master tumbler 23 be of sufficient strength that it can overcome the combined force of all of the springs associated with the conventional tumblers, as well as the spring 25' associated with the master tumbler. Accordingly, a lock constructed in accordance with'the persent invention is more difficult to pick than a conventionallock.

It will be apparentthat the master tumbler may take the place of one of the conventional tumblers, or may constitute an additional tumbler. It will also be apparent thatv the master tumbler may occupy any of the tubuler positions, and that the one-way connection between the master tumbler and the various conventional tumblers may be of various forms.

Accordingly, while various embodiments of the invention have been disclosed, many modifications will be apparent, audit is intended that the invention beeinterpretedias including. all modifications which fall within the true spirit and-scope of the invention.

What is claimed isi 1. In a key-operated'lockof the type having a bolt and a plurality of tumblers individually movable through different predetermined distances from normal, boltrestraining positions to bolt-releasing position, against biasing forces, bycorresponding portionstof atoperating key, the-improvement which comprises:

a mastertumbler.mounted-adjacent to the other tumblers and movable from normal, bolt-restraining position to bolt-releasing position by the key, said master tumbler being so proportioned and positioned that-the bolt is restrained against opening movement only by said master tumbler except when said master tumbler is in bolt-releasing position; and

means providing a one-way connection between said mastertumbler and the other tumblers such that movementof said master tumbler from normal position to bolt-releasing position is necessarily accompanied by movementof the other tumblers away from their normal positions, and movement of the other tumblers from their normal positions may be independent of movement of said master tumbler.

2. Ina key-operated lock of the type having a bolt and a plurality of tumblers pivotable about-a common axis and'having arcuate edges of equal radius which are engageable with a bolt edge toprevent opening movement thereof, and-wherein the tumblers are pivotable through different predetermined angles from normal positions, against biasing forces, by corresponding portions of a operating key to align a radial notch in the edge of 4 a each tumbler with the bolt edge to permit retraction of the bolt, the improvement which comprises:

a master tumbler mounted adjacent to the other tumblers for simultaneous pivoting movement about the same axis by the key, said master tumbler having a radius sufficiently greater than that of the other tumlers that the bolt edge may engage only said master tumbler until a notch in the master tumbler has been aligned with the .bolt edge, andthe bolt edge has entered that notch to a depth such that the bolt edge rides on the other tumblers; and

means providing a one-way connection betweenvsaid master tumbler and the other tumblers such that lock-opening movement of said master tumbler is necessarily accompanied by movement of the other tumblers away from their normal positions, and lock-opening movement of the other. tumblers may be independent; of movement of said-master tumbler.

3. In a key-operated lock of the-typevhaving a bolt and a plurality. of tumblers pivotable about'acommon axis and having arcuate edges of equal radius which are engageable with a .bolt edge to .prevent openingmovement thereof,- andiwherein the.- tumblers are ,pivotable through different predetermined angles from normal positions, against biasing forces, by correspondingportions of anoperating key toalign a radial notchin the edge of each tumbler with the bolt edge to permit retrace tion' of-the bolt; the improvement which comprises:

a master tumbler mounted adjacent to the: other tumblers for simultaneous pivoting movement about the same axis by the key, said master tumbler'havinga radius suificiently greater than that of the other tumblers that the bolt edge-may engage-onlysaid master tumbler until a notchiin the master tumbler has:been aligned with the bolt-edge and the bolt edge has entered that notch to a depth such that-the bolt edge rides on the other tumblers;.and

a member projecting from said master" tumbler and extending past and in closed proximity tosthe other tumblers such that lock opening-movement of'said master tumbler is necessarily accompaniedby movement of the other tumblers away from their-normal positions, and lock-opening movement ofthe other tumblers may be independentof movement of'said master tumbler,

References Cited by the Examiner UNITED STATES PATENTS 8,379 8/1878 Taylor 70 -8l 1,439,012 12/1922 Long 70-.3'56 1,793,254 2/1931 Shann 70-355 2,262,140 11/1941 Harvey 70-81 ALBERT H. KAMPE, Primary Examiner, 

1. IN A KEY-OPERATED LOCK OF THE TYPE HAVING A BOLT AND A PLURALITY OF TUMBLERS INDIVIDUALLY MOVABLE THROUGH DIFFERENT PREDETERMINED DISTANCES FROM THE NORMAL, BOLTRESTRAINING POSITIONS TO BOLT-RELEASING POSITION, AGAINST BIASING FORCES, BY CORRESPONDING PORTIONS OF A OPERATING KEY, THE IMPROVEMENT WHICH COMPRISES: A MASTER TUMBLER MOUNTED ADJACENT TO THE OTHER TUMBLERS AND MOVABLE FROM NORMAL, BOLT-RESTRAINING POSITION TO BOLT-RELEASING POSITION BY THE KEY, SAID MASTER TUMBLER BEING SO PROPORTIONED AND POSITIONED THAT THE BOLT IS RESTRAINED AGAINST OPENING MOVEMENT 